Expression of amphipathic protein (SAPI) from weet pepper for induction of resistance to Xanthomonas Campestris pv. Musacearum in banana

Abstract

Bananas and plantains constitute the most important staple food crop in sub-Saharan Africa. They are also a source of income for millions of people in this region. The livelihoods of millions of Ugandan farmers have been threatened by the recent outbreak of the Banana Xanthomonas wilt (BXW) disease caused by Xanthomonas campestris pv.musacearum. BXW is currently the most destructive emergent disease in Uganda, causing up to 100% plantation loss where no control measures are employed. It attacks all banana cultivars, including East African Highland Bananas (EAHBs) and there is no banana cultivar that is resistant to BXW. Due to lack of resistant cultivars in the available germplasm, coupled with the high infertility of the triploid banana cultivars, genetic engineering seems to be the most feasible way of introducing resistance into banana germplasm. This study reports Agrobacterium-mediated transformation of embryogenic cell suspensions of two banana cultivars ‘Nakinyika’ (EAAAA) and ‘Sukali Ndiizi’ (ABB), using amphipathic protein gene (sap1) that confers resistance against plant Banana Xanthomonas Wilt diseases. Transformed cells were selected on kanamycin supplemented medium and regeneration frequencies of 62% and 38% were observed for cultivars ‘Nakinyika’ and ‘Sukali Ndiizi,’ respectively. The presence of sap1 gene was confirmed by PCR analysis of transformed lines. The integration of sap1 gene into the plant genome was confirmed using Southern blot analysis. The efficacy of sap1 gene was tested by evaluating the transgenic lines for resistance against BXW using in vitro plantlets under laboratory conditions. The preliminary results obtained suggest that sap1 gene could provide significant resistance to BXW in banana.